1. Field of the Invention
The invention lies in the field of semiconductor technology and pertains, in particular, to a semiconductor component with a drift zone that conducts current in the lateral direction.
One of the most important market segments for smart power ICs is motor drives. Such control drives use, among other things, so-called half-bridge inverters. Due to the fact that these inverters need to be designed for voltages of a few 100 volts, IGBTs (Insulated Gate Bipolar Transistor) with lateral current conduction are generally used as switching elements. Despite their comparatively compact design, the IGBTs take up significantly more than half of the total chip surface of the respective half-bridge inverter (see, for example, M. Stoisiek et al., xe2x80x9cA Dielectric Isolated High-Voltage IC-Technology For Off-Line Applicationsxe2x80x9d, Proc. 1995 Int. Symposium on Power Semiconductor Devices and IC""s, Yokohama (1995), pp. 325-329; FIG. 8). To be able to produce half-bridge inverters and other high-voltage smart power ICs (reverse voltage Vbr greater than 200-600 volts) more economically, the material costs need to be reduced, and hence, in particular, the surfaces of the drift zones of the power semiconductor components of the IC need to be significantly reduced.
By using the so-called resurf principle (reduced surface field principle)xe2x80x94see Appels and Vaes, xe2x80x9cHigh Voltage Thin Layer Devices (Resurf Devices),xe2x80x9d IEDM Tech. Dig., 1979, p. 238xe2x80x94the distribution of the electrical field on the surface of a semiconductor component can be influenced in a targeted fashion. This technique allows the production of compactly designed components with a high blocking capability and with comparatively thin semiconductor layers receiving the field.
2. Brief Summary of the Invention
The object of the invention is to provide a semiconductor component that conducts current in the lateral direction which overcomes the above-noted deficiencies and disadvantages of the prior art devices and methods of this kind, and the drift zone of which, irrespective of whether it is designed as an MOS transistor, an IGBT, a thyristor or a diode, should take up a much smaller surface at a predetermined reverse voltage than the drift zone of the corresponding component known from the prior art.
With the above and other objects in view there is provided, in accordance with the invention, a semiconductor component, comprising:
a substrate formed of a first semiconductor material having a given electrical breakdown field strength and carrying a first insulator layer having a surface;
a second layer covering at least a part of the surface of the first insulator layer, the second layer being formed of a second semiconductor material having an electrical breakdown field strength higher than the given electrical breakdown field strength of the first semiconductor material;
the second layer having a first region in contact with a first electrode and doped to be electrically conductive, and a second region in contact with a second electrode and doped to be electrically conductive, the second layer extending in a first lateral direction so as to form a drift zone between the first region and the second region;
a second insulator layer doped to be electrically conductive and covering the drift zone; and
a control element conductively connected to one of the first and second electrodes and arranged in a portion of the substrate not covered by the second layer.
In accordance with an added feature of the invention, the control element is a MOS structure.
In accordance with an additional feature of the invention, the first region has a multiplicity of subregions of a corresponding conductivity type, the subregions are spaced apart from one another in a second lateral direction orthogonal to the first lateral direction, adjacent subregions are insulated from one another by contact regions of an opposite conductivity type, the control element has a first connection conductively connected to each of the subregions and a second connection conductively connected to each of the contact regions.
In accordance with another feature of the invention, the first and second electrodes are each a comb-shaped electrode making contact with the subregions and the contact regions, respectively.
In accordance with a concomitant feature of the invention, a product of a doping (in cmxe2x88x923) and of a thickness (in cm) of the second layer in a region of the drift zone is between 1013 cmxe2x88x922 and 5xc2x71013 cmxe2x88x922.
The invention permits smart power ICs, for example, to be produced much more economically on account of the significantly smaller surface of the power semiconductor components, or permits a larger number of components with the same blocking ability to be integrated on a smaller chip surface.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a semiconductor component, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.